1. Field of the Invention
The present invention relates to a semiconductor device.
2. Related Background Art
Conventionally, semiconductor devices such as an LED and an LD, in which a compound semiconductor such as a III-V semiconductor crystal or the like is used as a material, have been widely used. At the same time, studies of a semiconductor device in which silicon is used as a material have also progressed. A light-emission intensity of single-crystal silicon which emits light of 1.13 μm at room temperature is very low as compared to that of the above-described compound semiconductors. It is known, however, that porous silicon or the like, for example, in which the silicon is used as a material, emits a visible light of which intensity is large as compared to the single-crystal silicon. Therefore, as is described in the Patent Document 1 (Japanese Patent Application Laid-open No. Hei 08-139359), for example, research and development in a semiconductor device in which the porous silicon or the like is used have progressed.